The present invention relates to optical scanners and more specifically to a barcode scanner with a dual-surface polygon.
Optical scanners are well known for their usefulness in retail check out and inventory control. Optical scanners generally employ a laser diode, the light from which is focused and collimated to produce a scanning beam. A mirrored polygon directs the beam against a plurality of stationary mirrors, and collects the beam after it is reflected by an item bearing a barcode label. A motor rotates the mirrored polygon, and a detector receives the returning beam. The pattern produced by such a scanner is characterized by lines oriented at various angles to one another.
The performance of a scanner is related to total scan line length S. Total scan line length S is the sum of the lengths s of all scan lines produced by the scanner.
Individual scan line length s is related to optical path length L and angular coverage Θ of the scan line,s=L×Θ.The optical path length L is the distance between the facets and the scanned object. A typical polygon has external facets.
It would be desirable to provide a barcode scanner with a polygon that increases total scan line length S.